Gasoline compositions have traditionally been formulated to improve the performance of carburetor and throttle body injected engines. Beginning in about 1984, electronic port fuel injected engines were commonly introduced by automobile manufacturers. Shortly thereafter, in about 1985, problems began to be reported with intake valve deposits in electronic port fuel injected engines, which problems are characterized by hard starting, stalls, and stumbles during acceleration and rough engine idle.
Conventional commercial gasoline additives contain nitrogen. The nitrogens are attached to a polymer, and the nitrogens are separated by two or three carbons. This structure provides a potential for chelation. However, steric hinderance reduces chelatability in conventional additives since the polymer is attached through one of the nitrogen atoms.
Without limiting the invention by theories of operation, it has now been discovered that chelatability is advantageous for its deposit reducing tendencies. Accordingly, it would be desirable to have a new gasoline additive for unleaded fuel compositions which have increased chelatability and thus reduce or eliminate undesirable intake valve deposits in electronic port fuel injected engines. Also, since some carburetor and throttle body injector engines will still be in use for the foreseeable future, it would be desirable if such fuels could also be compatible with these engines.